A panel of a material is transported in operative proximity to an air knife having a nozzle and a curved Coanda surface, such that the panel is folded over the curved Coanda surface as the material is transported in a machine direction. The panel can be folded to a variety of angles and can comprise a refastenable fastening component. Air knives are employed in various methods for folding garment side panels and forming prefastened garments, such as refastenable pants.